The present invention relates to systems and methods for treating process material and, more particularly, to systems and methods for treating municipal domestic or septage liquid sanitary waste material, medical waste material, food waste, commercial farm animal waste, reclaimed paper and the like.
Historically, septage waste has been trucked either to conventional publicly owned waste water treatment plants (WWTP) or has been directly applied to farm land.
Direct application of raw septage waste to farmlands has the potential for serious problems. Direct application can contaminate ground water and has a high probability of disease transmission to people via animals and insects.
The activated sludge in a conventional WWTP treats the normal levels of raw residential sanitary waste. When high concentrations of septage waste is trucked in from outside of the WWTP community, the negative impact upon the WWTP plant is threefold: (1) the culture or activated sludge is stressed by the anaerobic high concentration waste which at times could result in final effluent limitation exceeding capacity of the WWTP; (2) by allowing waste that is generated outside of the of WWTP community the useful life of the plant is shortened due to the increase of required treatment capacity (this can lead to premature replacement or expensive expansion of the WWTP); and (3) a public WWTP and private septic hauling business sometimes have incompatible management goals.
U.S. Pat. No. 4,919,814 to Carnahan, et al. discloses a system and method for treating septage (i.e., wastewater collected from septic tanks and similar installations) which utilizes a reactor tank for treating the anaerobic wastewater with an oxygen-containing fluid so as to substantially increase the dissolved oxygen content and thereby render the wastewater aerobic and suitable for input into a municipal wastewater treatment facility. Volatile gases are drawn off from all of the reactor tanks and placed into a treatment tank for a reduction of the bacterial and odor levels by reaction with a chlorine-containing water output of the municipal wastewater treatment facility.
U.S. Pat. No. 5,543,050 to Roshanravan discloses a system that uses both aerobic and anaerobic treatment processes on grease-trap waste contents. The system initially screens the wastewater to remove larger solid-waste matter particles. The wastewater is next anaerobically and aerobically processed. The anaerobic and aerobic processes use dissolved air flotation clarifiers utilizing gas entrained water to remove solid-waste matter from the wastewater. The anaerobic and aerobic processes also use digester apparatus which break down the solid-waste matter of the wastewater. The anaerobic digester uses anaerobic biological processes for breaking down the solid-waste matter while the aerobic digester uses aerobic biological processes. The two by-products of this system, the clarified wastewater and the composted solid-waste matter, are both more ecologically acceptable alternatives than dumping the grease trap contents into a landfill site.
U.S. Pat. No. 6,015,496 to Khudenko, describes a method and apparatus for in-sewer wastewater treatment comprising steps of largely spontaneously growing acidogenic bacteria in sewer lines and providing methanogenic bacteria in those lines. Methanogenic bacteria can be grown using wastewater, solid, or other waste, or other organic feedstock as a substrate. Methanogenic bacteria can be cultivated at a wastewater treatment plant or at other locations in special reactors, or provided from anaerobic wastewater pretreatment plants. Digestion gases can be either vented out or collected and used.
U.S. Pat. No. 6,126,827 to Johnson, Jr., et al. discloses a wastewater treatment system which can be used to treat high-strength septage, sewage and industrial wastewater. The wastewater treatment system consists of three major components. In the first component, solids are separated from the liquid component of the wastewater being treated. The separated solid portion is removed to a composting component wherein it is turned into a commercially useful compost material. The liquid component is subjected to a two part treatment wherein the first part of the treatment is carried out in a sequencing batch reactor and the second part is carried out in at least one reed bed. In an alternative embodiment of the present invention, the various components of the wastewater treatment system are in modular form.
U.S. Pat. No. 6,776,914 to Hickey discloses a process for treating liquid septage and other biosolids having the steps of placing a known amount of liquid septage in a tank, mixing in a sufficient quantity of alkaline material to raise the pH to a desired level, flocculating the septage, storing the pH adjusted septage for a predetermined period of time, thickening the septage, de-watering the septage, and pasteurizing the resultant liquid effluent and de-watered solids cake. The process for treating liquid septage and biosolids disclosed by the current invention meets the Class A vector attractant reduction and pathogen reduction requirements mandated by the U.S. EPA. The end product of septage and other biosolids treated using the process disclosed by the current invention can be sold as fertilizer, and utilized without any additional permits.
U.S. Pat. No. 6,558,550 to Kelly discloses a process and apparatus for the treatment of septage, particularly grease trap waste. The inventive process will convert the septage into biosolids (sludge) and water dischargeable to the environment. The treated septage achieves pathogen reduction, and reduced vector attraction. Treatment of septage by pasteurization causes the destruction of harmful pathogens. Pasteurization of septage having high water content provides for even temperature elevation and distribution of heat within the thermal mass of the septage allowing for consistent pathogen destruction. An alkaline compound is utilized to form a filter cake from the solids fraction of the pasteurized septage preventing vector attraction, while producing a beneficial bio-solid. The liquid fraction of the septage is treated by biological process allowing for its discharge into the environment.
U.S. Pat. No. 7,070,693 to Kelly discloses a process and apparatus for the treatment of septage. The process converts the septage into biosolids (sludge) and water dischargeable into the environment. The treated septage achieves pathogen reduction and reduced vector attraction. Treatment of septage by pasteurization causes the destruction of harmful pathogens. Pasteurization of septage having high water content provides for even temperature elevation and distribution of heat within the thermal mass of the septage allowing for consistent pathogen destruction. An alkaline compound is utilized to form a filter cake from the solids fraction of the pasteurized septage preventing vector attraction, while producing a beneficial biosolid. The liquid fraction of the septage is treated by biological process allowing for its discharge into the environment.
U.S. Pat. No. 7,169,306 to Porteous et al. discloses an aerobic digester system in a wastewater treatment plant that is made more versatile for different conditions by addition of an equalizer basin or in some embodiments, a bypass pipe. If in-feed is received from a sequential batch reactor or from a concentrated septage, for example, the equalizer basin can contain one batch, and then deliver the batch out incrementally to a gravity thickener basin. The equalizer basin also enables the gravity thickener of the system to be removed from service when needed, providing increased flexibility for the system. Importantly, the equalizer or bypass enables versatile modes of operation so that a plant designed for a larger, later flow can operate at an initially low flow or at several levels of flow before reaching the largest design flow.
United States Patent Application No. 20060086662 by Ogden discloses waste treatment systems and methods of using them to treat septage, domestic sludge or both are disclosed. Certain examples provided herein relate to waste treatment systems that include a plurality of stages, such as, for example, a plurality of ecosystems, configured to treat domestic sludge, septage or both.
United States Patent Application No. 20060222463 by Subbarayan, et al. discloses landfills and their methods of operation. Through the controlled introduction of septage into solid municipal waste, refuse decomposes faster to achieve additional landfill space. A business method of operating the landfill is also disclosed.
The present invention allows for the construction of remote multiple privately owned site-specific sanitary septage treatment plants (SSTP). The SSTP plants typically will only receive sanitary septage waste generated from locations outside of the established WWTP community. The SSTP with an augmented primary treatment will reduce the high strength raw septage waste concentration to SSTP secondary concentrations close to that of a WWTP secondary. These SSTP plants typically and preferably are located in the local market or service area to minimize tanker drive time. The nutrients can be recovered and then recycled into the earth's biomass.
This high concentration sanitary septage waste is approximately 10 times the normal strength of raw waste entering the WWTP. The WWTP process is stressed by the anaerobic high concentration waste. Waste from uncontrolled sources that is generated outside of the WWTP community can shorten the life of the WWTP plant due to reduced capacity. In addition, management of a public WWTP and private septic hauling business at times are incompatible due to different operational parameters and goals.
Accordingly, there remains a need for systems and methods for the effective and efficient treatment of septage taking into account the distribution of septage sources, delivery volume and schedules, and the required treatment and the associated retention times and throughput requirements of each treatment stage, and that of the system as a whole.